Automatic timing device



Nov. 8, 1932.

w. s. M GUIRE AUTOMATIC TIMING DEVICE Filed April 15, 1951 2 Sheets-Sheet l mvsm'on ATTORNEYS Nov. 8, 1932. w. s. MCGUIRE AUTOMATIC TIMING DEVICE Filed April 15, 1951 2 Sheets-Sheet 2 Mia ATTORNEYS Patentecl Nov. 8, 1932 UNITED STATES PATENT OFFICE WALTER S. MCGUIRE, OF SHADYSIDE', OHIO, ASSIGNOR OF ONE-THIRD T CHARLES WELLS RODEFER, OF SI-IADYSIDE, OHIO AUTOMATIC TIMING DEVICE Application filed April 15, 1931.

This invention relates to an automatic timing device especially adaptable for use in photography or the printing of pictures from negatives and has for the primary object, the provision of means for controlling the illumination of an electric printing lamp and which is capable of varying the length of time the lamp may be illuminated to permit varying exposures to be made and the successful development of pictures thereby and the employment of printing paper or mate rials of varying sensitivity.

Another object of this invention is the provision of a motor driven circuit breaker which i may be easily and quickly adjusted to control the illumination of the printing lamp over various periods of time and to permit the illumination of the lamp for periods of time in a fraction of a second.

With these and other objects in view, this invention consists in certain novel features of construction, combination and arrangement of parts to be hereinafter more fully described and claimed.

For a complete understanding of my invention, reference is to be had to the following description and accompanying drawings, in which-- Figure 1 is a side elevation illustrating an automatic timing device constructed in accordance with my invention.

Figure 2 is a similar view with one wall of the housing removed.

Figure 3 is a sectional view taken on the line 3-3 of Figure 1.

Figure 4 is a perspective view illustrating a portion of the circuit breaker.

Figure 5 is a perspective View illustrating a stop.

Figure 6 is a diagrammatic View illustrating the wiring diagram.

Referring in detail to the drawings the numeral 1 indicates a housing having a re movable wall 2 secured in position by screws or other suitable fasteners 3. A vertical support 4 is mounted in the housing 1 and supports a conventional type of electric motor 5, the shaft of which has secured thereto a grooved pulley 6 and on which is formed the hub 7 of a fan 8. The fan 8 is of the two- Serial No. 530,417.

blade type having the free ends oppositely curved as shown in Figure 3 and is adapted to provide a load on the motor or a retarder thereto, so that the motor will more readily change its speed of rotation in accordance with the variance of the amount of electrical current thereto.

A support 9 is located in the housing 1 and spaced from the support 4; and cooperates therewith in rotatably supporting a circuit breaker 10 which includes a shaft 11 journalled in suitable bearings of the supports 4 and 9 and has associated therewith a friction clutch 12 which is in turn associated with a grooved pulley 13, and the latter has trained thereover an endless belt 14c which also passes over the grooved pulley 6. A nut 15 is threaded to the shaft and has one end of a coiled spring 16 bearing thereagainst while the opposite end of the coiled spring bears against the pulley 13 for cooperating with the frictional clutch 12 in establishing a frictional drive between the grooved pulley 13 and the shaft. The purpose of the frictional clutch 12 which may be of any desired construction is to permit the rotation of the shaft 11 to be stopped and the operation of an electric motor 5 continued. The frictional clutch 12 will drive the shaft from the pulley 13 until said shaft is locked against rotation or the resistance to rotation is increased to a predetermined amount.

The circuit breaker 10 includes a commutator 17 of tubular formation having secured in one end by a tongue 18 a plate 19 provided with a centrally arranged opening 20 to reccive the shaft 11 and the latter is secured to the plate 19 in any desired manner to cause rotation of the commutator with the shaft. A pivotally mounted brush 21 is located on the support 9 and the free end of which engages the periphery of the commutator 17 and is adapted to be moved laterally in one direction relative to the periphery through means of an operating arm 22 pivotally mounted on the outer face of the housing 1. A pin 23 establishes connection between the operating arm 22 and the brush 21 so that when the operating arm is moved over a scale 24 on the outer face of the housing, the brush will be adjusted over the periphery of the commutator accordingly. The commutator 17 is provided with a V-shaped cut-out portion as shown in Figure 4 for the purpose of pro viding contact surfaces of different lengths for the brush 21 to engage, thus it will be seen that according to the position in which the brush is placed the period of time in which a circuit will be completed by the circuit closer may be varied. The brush 21-is constructed from laminated material or from a plurality of closely related strips as shown in Figure 3 so that the contact end of th brush will have a plurality of bearing surfaces to engage the periphery of the commutator to reduce the possibility of sparks or arcs being created between the brush and the periphery of the commutator. A spring contact 22' constructed of laminated material engages the plate 19 of the commutator and is carried by a binding post bridge 23" and it is to be understood that the brush 21 .is placed in an electric circuit along with the contact brush 22 and which will be hereinafter more fully described.

A resilient catch 25 has one end secured in the housing 1 and its other end is bifurcated and bent angularly to form ears 26 and 2'7.v The car 26 is positioned inwardly of the ear 27 to form a space between said ears through which a stop may pass. An extension 28 is formed on the ear 27 to engage the stop. The stop referred to is a pin 29 secured to the end of the commutator or the plate 19 thereof and when the spring catch 25 is in its normal position, the extension 28 of the car 27 engages the pin and holds the commutator against rotation, and when the catch 25 is flexed, the pin 29 passes between the ears 26 and 27 and the commutator makes one complete revolution and should the spring catch 25 be still held in a flexed position the pin engages the car 26 to.

prevent further rotation of the commutator, and should the catch 25 be released from a flexed position and allowed to return to a normal position, the extension 28 will engage the pin and prevent the commutator from rotating beyond one revolution. A flexible finger piece 30 is secured to the outer face of the casing and carries a pin 31 extending into the casing to engage the spring catch 25 for the purpose of flexing the same so as to free the commutator for onecomplete revolution.

The device is adapted to be plugged into an ordinary house circuit which is indicated by the feed conductors 32 and 33 and they have connected thereto conductors 34: and 35. The conductor 35 is provided with a manually controlled switch 36 and is electrically connected to one of the brushes of the electric motor and also is connected to the movable brush 21 by a conductor 37 A conductor 38 is connected to the other brush of the electric motor and to an electric resistance 39 which is in turn connected to the conductor 34:.

The conductor 34 is connected to a photographic printing lamp40 and the latter is electrically connected to the commutator 17 by a conductor 41 and it is to be understood that the electric lamp 40 is placed in the usual printing rack or form now in useand in which is positioned the negative and sensitive paper for the picture to be printed upon by the rays of light from the electric lamp 40.

In operation, with the switch 36 in'c'losed position, the electric motor 5 is set in operation rotating the fan 8 and pulley 13 through the belt 14:. When a picture is to be printed in the usual manner by the rays of light from the lamp 40, th operator presses the finger piece 30 freeing the switch catch 25 from the commutator, permitting the commutator to make one complete revolution. The rotation of the commutator with the brush 21 in engagement with the periphery completes an electric circuit to the lamp illuminating the lamp sufiiciently long to cause a printing of the picture on the paper from the nega ive. It will therefore be seen thatthrough the operation of the lever 22 over the scale, the operator may vary the length of time in which the lamp is illuminated and due to the peculiar construction of the commutator and the means of only allowing the commutator to make one complete revolution, the illumination of the lamp40 may be varied to a fraction of a second thereby, permitting the operator to employ very sensitive materials and also to regulate the device according to the sensitiveness of the materials being em ployed.

It is further to be noted that this device is in the form of an attachment to be placed in circuit between the electrical source and any type of printing lamp or device which may be in use.

While I have shown and described the preferred embodiment of my invention, it will he understood that minor changes in construction, combination and arrangement of parts may be made without departing from the spirit and scope of my invention, as claimed. r

Having thus described my invention, what I claim is: r

1. An automatic timing device includ ng a housing and an electric circuit leading to and operating on an electric printing lamp, an electric motor in said housing, a fan ro tated by said motor to provide a retarder thereto, a manually controlled circuit breaker" connected to the circuit, a pivoted brush in the casing to engage the commutator and electrically connected to the circuit, means for moving the brush relative to the commutator for varying the periods of time of illumination of the lamp, and means for operating the commutator from the motor.

3. An automatic timing device including a housing and an electric circuit leading to and operating on an electric printing lamp, an

electric motor in said housing, a commutator journalled in the housing, a frictional drive hetvveen the commutator and the motor, an adjustable brush associated with the periphery of the commutator, means for ad ust1ng the brush relative to the commutator, and electric means connecting the commutator and brush to the circuit of the lamp.

a. An automatic timing device including a housing and an electric circuit leading to and operating on an electric printing lamp, an electric motor in said housing, a commutator ournalled in the housing and having its periphery out way to form contact surfaces of varying lengths, a pivoted brush to engage the contact surfaces of the commutator, means for adjusting the brush relative to the contact surfaces of the commutator, means for permitting the commutator to have a complete revolution each time it is manually released under the influence of the motor, and electric means connecting the commutator and brush to the circuit of the lamp.

An automatic timing device including a housing and an electric circuit leading to and operating on an electric printing lamp, an electric motor in said housing, a commutator journalied in the housing and having the periphery thereof cut away to form contact surfaces of varying lengths, a frictional drive between the commutator and the motor, a stop carried by the commutator, a pivoted brush movable over the contact faces of the commutator, means for operating the brush, means electrically connecting the commutator and brush to the circuit of the lamp, a spring catch in the housing, means on the spring catch to engage the stop for holding the commutator against rotation by the motor until the catch is flexed a turn to free the commutator for one revolution and to automatically stop the commutator after said complete revolution, and means carried by the housing for flexing the catch.

In testimony whereof I affix my signature.

\VALTER S. MGGUIRE. 

